1. Field of the Invention
The present invention relates to the collection, storage, and transportation and distribution of clean and renewable energy from fleets of vessels located in off-shore, ocean locations. Specifically, energy obtained from wind waves and ocean swells is converted to forms suitable for transportation to coastal and inland ports accessible by navigable waterways.
2. Background of the Prior Art
The use of floats to capture the largely untapped energy available from ocean waves has been known for many years. Most of these inventions were developed to provide either a direct linear linkage to a mechanical interface to do specialized tasks such as turning a shaft or piston, or pumping water to obtain a hydraulic head, etc. See U.S. Pat. No. 4,249,084, [1] 1,471,222. These devices tended to be mechanically complex and unsuited to efficiently couple energy over the broad spectrum of ocean wavelengths encountered in practical applications such as in U.S. Pat. Nos. 1,818,066, 1,169,356 and 1,647,025.
The more successful applications utilized wave conversion in conjunction with hydraulic systems with servomechanisms and turbo-electrical generators to adapt to a wider range of sea conditions including wave amplitudes and spectral wavelengths such as Hagen, [6], [7], Cockrell, [19] and Talya [15]. These patents are good examples of using efficient resonating systems in their designs. Talya uses various means of tuning groups of buoy type floats when given commands from a central computer. Each group is tuned to a specific band of frequencies. Hagan uses arrays of floats, each float within an array being resonant by virtue of its physical dimensions. Each float dimension encountering a wave front is a half wavelength at a design frequency. No adjustments are needed to passively resonate to a particular wavelength. Relative motion between, adjacent floats provide the kinetic energy that is transformed to an electrical form. It also accommodates a non-linear conversion characteristic thus accommodating a significant range of wave amplitudes.
McCabe, U.S. Pat. No. 5,132,421 (12) uses three barges for which the relative motion between the central barge and the outer barges or pontoons are used to pump high-pressure water to shore with which electricity is generated or water desalinated. Resonance is adjusted by changing the inertia of the system and damping response of the central barge. Damping is accomplished by underwater damping plates mounted on long shafts and with the other ends mounted to the central barge. The damping plates are screwed up or down the shafts as required. Inertia is changed by varying the ballast in the outer pontoons. Each deployment requires a priori knowledge of a location and adjustment to the predominant wavelengths at a site.
McCormick, in his patent application 20090084296 (20) uses three barges, each of different length, the middle barge has a length that is less than half of the forward barge length to achieve relatively large angular displacements between the two. The third barge is the longest of the three to provide directional stability to the system so that it faces into the incident waves. The motion of the hinged barges is used to drive pumps that draw in salt water and pump the water at high pressure to a reverse osmosis desalination plant that is located on shore or on the rear barge. The motion of the forward and rear barges is enhanced by using U-shaped tubes containing ballast water that have resistance valves to ballast water flow. The amount of ballast and the dimension of the tubes and control of the valves are used to adjust the resonant frequency of the system. The emphasis of the design is desalination. And like McCabe the system requires a priori knowledge of a location and adjustment to the predominant wavelengths at a site.
Perhaps the most mechanically sophisticated WEC in actual use at the present time is that of Yemm, [3]. This system consists of elongated, buoyant cylinders which form an articulated structure. The segmented structure has length which is of the order of the longest wavelength to be processed. Power is extracted from the relative rotational movement of cylinders induced by cross-coupling between perpendicular pairs of joints. A means is provided to vary the yaw angle to track the mean wave direction.
Heronemus, et al, [18] teach us the virtue of removing CO2 from the sea and air by using electricity generated at sea with wind driven generators and show us the possibility of storing hydrogen in the form of methane (or other hydrocarbon form) for its ultimate transport to land based facilities.
Functional Goals of the Invention
The functional goals of the invention are as follows: 1) convert renewable energy from the resources of the open ocean to a form useful in reducing dependence on petroleum sources; 2) use common facilities and personnel to perform energy conversion, storage, transportation and distribution; 3) contribute to the depletion of CO2 in the atmosphere; and 4) produce fuel products at a cost comparable to other alternative fuels and products 5) avoid competition for coastal space with other renewable fuel operations, avoidance of environmental destruction and visual impairment; and 6) avoid premature obsolescence of existing energy storage distribution infrastructure.
Comparison of the Invention Design Approach with Prior Art
Prior art has been directed to specialized conversion systems that were not required to be operated in areas beyond the reach of direct access to an electrical grid. For example, Hagan Salter [4], Talya and Yemm designs that are not suitable for producing substantial alternate energy fuels or transportation to remote markets without the use of electrical grids. These inventions also are restricted to coastal locations with lesser potential energy than the outer banks or open ocean locations. There are many competing renewable energy applications requiring coastal access like wind turbine farms and tidal current facilities which put practical limits on the number of future hydrokinetic system sites that may be available to meet the nation's needs. A new approach to wave energy conversion has been in the invention herein described that achieves efficiencies equivalent to that of stationary collecting installations but employs standard physical dimensions for vessels that can be and are built in large numbers and thus achieve an economy of scale.
Two conversion approaches are considered: 1) successive conversions to electrical, molecular hydrogen (H2) and a liquid hydrocarbon. The preferred hydrocarbon is methanol which is produced by the reaction of the H2 and carbon dioxide (CO2). The CO2 would be derived from waste gasses ordinarily discharged into the atmosphere by industrial plants, from sea water or the atmosphere. 2) The second method stores the electrical energy directly in ultracapacitors, or an ultracapacitor-lead acid battery hybrid.
The principal component of the hydrocarbon product produced by the first conversion method is hydrogen which has been proposed by many different groups as the “fuel of the future” and the subject of important international initiatives. Future applications are being planned in the transportation, industrial and military markets. Unfortunately, the storage, transportation, and distribution of hydrogen have been cited as the most significant technological barriers to its widespread implementation. Any number of proposed renewable energy systems dependent on locations that are remote from their markets have encountered this problem which, if implemented would result in premature obsolescence of existing infrastructure, safety and environmental problems. The concept described herein provides a means of transition to petroleum independence by providing a number of end-user energy forms, including methanol, methane, ethanol, dimethyl ether (a diesel substitute), gasoline, and jet engine fuel.
Total Cost Considerations
This concept development chosen was to a large extent influenced by the problems of other renewable energy projects. A “well to the tank” approach has been adopted that considers not only the actual capital and operating costs, but the costs of storage, transportation, distribution, infrastructure changes and maintenance. What is often not considered by organizations proposing renewable energy is that of the cost of removal and retirement of permanent structures. Examples of the latter include seabed restoration, scrapping of permanent coastal foundations typical of offshore wind farms, permanent anchoring systems of wave energy conversion (WEC) systems, etc. Disruption of the coastal fishing industry can occur from “wave energy farms” permanently anchored and operating close to shore that require submerged power cables for interconnection to power grids. Of course, the environmental costs are more difficult to measure, but exist. Visual impairment caused by near shore wind farms, intrusion into public recreational facilities, and impairment of waterways by tidal energy systems are detriments to their employment. The system of vessels that comprise the subject design removes many of the previously mentioned obstacles as the operation is performed in open and unobstructed ocean locations, and out of sight of land, if required. It uses self-propelled vessels thus requiring a minimum, or no use of installation and support vessels, which are at present powered by petroleum based fuels. Maintenance actions can be integrated into routine shore side operations. The vessels have a residual value as general transportation vessels at the end of the useful life of the ocean stations. It is noted that the comparative measurement of the true cost of energy between renewable energy systems is highly dependent on where the measurement is taken. At the present time the cost “at the tank” of transportation systems must consider the cost of conversion from grid supplied energy for vehicles using renewable liquid fuel. In addressing comparative costs of renewable energy system, considerable guidance has been obtained from the comprehensive study performed by the National Academy of Engineering and the National Research Council, “The Hydrogen Economy: Opportunities, Costs, Barriers and R & D Needs”. [Ref. 21].